def fun(x="dx",y="dy"):
print "fun------"
print x
print y
fun()
fun("aa","bb")
fun(x="ha",y="la")
ct = dict(x="haha",y="lala")
fun(**ct)
==================================
fun------
dx
dy
fun------
aa
bb
fun------
ha
la
fun------
haha
lala
=============================
原文：http://www.cnblogs.com/mhc-fly/p/7227912.html